Drying oven



y 15, 1956 R. E. MOULE 2,745,190

DRYING OVEN Filed NOV. 15, 1952 2 Sheets-Sheet l l I l 3 INVENTOR.

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R. E. MOULE DRYING OVEN May 15, 1956 2 Sheets-Sheet 2 Filed Nov. 15, 1952 INVENTOR. fax flame Y United States Patent DRYING OVEN Rex E. Moule, Holden, Mass.

Application November 15, 1952, Serial No. 320,688

7 Claims. (Cl. 34-12) This invention relates to a new and improved drying oven particularly adapted for the continuous processing of materials. The specific embodiment of the present invention resides in an apparatus for drying pads or padding of metallic wool which have been coated or sprayed with a tacky adhesive substance.

After the coating, it is necessary as a part of the process to initially partially dry the coated padding which is in the form of an endlessly moving apron; the apron is then sized by being passed between rollers or other compressing means that limit the same to a definite thickness, and after such partial drying or curing and sizing, the continuously advancing apron is cut into relatively short pieces of the desired length and width, whichpieces are then thoroughly cured to finish form, ready for manufacture as desired into mattresses, upholstery, padding or other articles.

In the present invention, there is provided a new and improved oven for accomplishing the part of the process outlined above, and this oven comprises an elongated horizontal chamber having a laterally extending leg at each end so that the form of the oven comprises a flat U; an endless conveyor runs through the top of this housing from end to end and carries the continuously moving apron therethrough near the top thereof and the same emerges at the opposite end after passing in a straight line through the oven, whereupon it is sized and cut as above stated, stacked on trucks, and started on its way on a slow travel through an inlet door which is in one of the legs, passing completely through the housing or oven under the continuously advancing apron above it and out the other door completely cured.

One of the objects of the present invention is to provide an improved oven of the class described above, said oven being provided with one or a plurality of heatproducing furnaces having means for blowing heated gases or air into the chamber in conduits that are U- shaped; each having a leg at either side of the elongated housing and each having a transverse connecting portion between the side legs so that the warm air is blown in at both sides of the housing and directed into the middle thereof; and the provision of the above-described oven, in combination with cool or exit conduits of similar shape located, however, at the U-shaped entrance and exits, the latter outlets creating a slightly negative pressure for returnof air ,to the furnaces whereby when the doors are opened to admit or discharge the pad-filled trucks, the hot air does not tend to escape but on the other hand a small amount of atmospheric air is drawn into the outlets and directed solely to the furnaces and not to the interior of the oven.

Other objects and advantages include the provision of special purpose doors at the entrance and exit of the oven and special outlets for moist air which is adapted to be exhausted in relatively small quantity from the top of the conveyor adjacent to the in-coming continuously moving apron or belt of just coated material.

2,745,190 Patented May 15, 1956 Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings, in which Fig. 1 is a view in front elevation of an oven, according to the present invention;

Fig. 2 is a top plan view thereof with the top removed;

Fig. 3 is an enlarged end view;

Fig. 4 is a perspective view illustrating the passage of the warm air through the oven;

Fig. 5 is a perspective view of the exit door; and

Fig. 6 is a view in front elevation of the inlet door.

The housing forming the main portion of the oven in the present case comprises a rear wall 10, a shorter front wall 12 and the ends walls 14 and 16. At each end of the enclosure, there is a leg extending outwardly as at 18 and 20, making the entire oven appear U-shaped in plan and forming a bay at 22 which accommodates furnaces 24, 26 and control mechanisms not herein disclosed.

The leg at 20 is provided with an admission door 28 which closes the oven at the admission end thereof and there is another door 29 that closes the exit door in leg 18. The door 23 may take any convenient form and is here shown in the nature of an upwardly opening overhead doo-r; but the exit door 29 is of the type disclosed in Fig. 5 and opens outwardly on hinges, so that material inside the oven and proceeding through the main body thereof and outwardly through leg 18 may be automatically opened by such material so that there will be no stalling of the relatively bulky material that is processed by the present construction.

Each furnace 24, 26 is provided with an air inlet 30 and these may be opened or closed according to need. In Fig. 1, reference numerals 32 indicate the stack for the furnace.

As shown in Fig. 2, the hot air proceeds through pipes 34 from the top parts of the furnaces into the interior of the oven, which of course is provided with a roof as will be apparent. Each of the pipes 34 is provided interiorly of the oven with a U-shaped warm or heat distributing conduit best shown in Fig. 4 and comprising vertical legs 36, horizontal legs at the top at 38, and a rear vertical leg 40. Each of these parts 36, 38 and 40 is provided with air emission holes as clearly shown and the hot air therefor travels in the direction of the arrows to maintain the interior of the oven heated. This air, of course, comes from the conduits 34 through the apertures 42 (see Fig. 4).

The hot air as described is thus distributed throughout the oven and escapes through the cold air outlets generally indicated at 44, each of which is U-shaped just as are the parts 36, 38 and '40, but in this case the air is uniformly extracted from the oven and returned to the furnaces through conduits 46 (see particularly Fig. l).

The air outlets are arranged closely adjacent the inlet and outlet doors so that when either or both of these doors is opened as is necessary from time to time to enter material into the oven and to extract it, there is no outrush of hot air. Due to the negative pressure provided by the air outlets 44, a little air will flow into the oven through the open doors but such air will be taken into conduits 44 and thence directly through pipes 46 into the furnaces for heating and circulation as described.

In the ceiling of the chamber, there are a series of outlet conduits generally indicated at 48 and these are all connected to a header 50 having an exhaust fan which runs at low speed and gradually extracts a small amount of warm air from the top of the oven which warm air is very moist, and thus the oven may be kept in as substantially dry a condition as may be required for the process.

The screens at 52 represent the area of escape of warm moist air but each of the conduits 40 at the ends of the oven have larger screens 54, which, however, are capable of being shut off by means of a hand-operated valve or the like .which maybe operated from the front of the oven as at 56 to cut down the volume of the exiting of the moist air.

The reason that the air at the top of the oven is moist is due to the progress of the endless continuously advancing metallic wool which has just been sprayed and this enters at the end 60 (see Fig. 1) on an endless con veyor .62 and is carried along through the oven just under the ceiling thereof to an exit point at 64. This padding of metallic wool is shown at 6,6 in Fig. 3 as it exits from the top part of the oven in partially cured condition and is then dried and cut as above explained.

The reference numeral 68 represents a track on which mat or pad-laden trucks may progress from the leg 20 through the oven to the leg 18 thereof and the same is driven as by an endless chain 70 which automatically picks up the trucks as they are manually pushed in at the door 28.

An important aspect of the invention resides in the fact that the flow of heated air is warmed in the furnaces but is not at any time in contact with the flame or products of combination. This is advantageous in that the product being processed is not affected by the soot, flame variation, etc., but this has heretofore been thought to be impossible because of insufficient heat to accomplish the curing, drying, etc. of the material. However, due to the construction of the present housing, oven, and ducts, furnaces of conventional design and ordinary capacity have been found to accomplish the purposes described, particularly as to metallic Wool coated with adhesive or rubbery material as disclosed previously.

The positions and operation of the warm air inlets and cooler air returns, plus the construction of the moist air outlets all cooperate to achieve the new result here explained.

It will be seen that this invention provides a mechanism for the optimum heating and curing processes of material of the class described, while at the same time the oven is extremely economical as to the heat as only just so much hot moist air escapes as is required to keep the oven at correct degree of aridity. Also the door and a conduit arrangements are made so that hot air does not rush out and cold air does not rush into the oven but is taken care of as above described in order to provide for more eflicient operation of the apparatus and for the novel and advantageous result of providing drying and curing by indirectly heated streams of air.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. A drying oven comprising a U-shaped housing struc ture, a portal at the foot of each leg of the U, means providing a U-shaped trackway from one portal through the housing to the other portal, a door for each portal, heating means in the corner formed by each leg and the closed end of the U, an air outlet at each portal connected to the intake side of its respective heating means, a pair of spaced air inlets in the closed end of the U connected to the output side of the respective heating means, whereby heated air enters the housing centrally thereof and exists at each end thereof at the portals.

2. The oven of claim 1 including an overhead conveyor'rneans for uncut material in sheet form passing from end to end of the housing near the top thereof and a moist air outlet in the top of the housing, and carts movable on the trackway for carrying out material in stacked from thereon.

3. T he oven of claim 1 including an overhead conveyor means for material passing from end to end of the housing near the top thereof and a moist air outlet in the top of the housing, and means for supplying air to the heating means in excess of the air returning thereto by means of the outlets, said trackway being located on the fioor of the oven.

The oven of claim 1 wherein one door is an exit door only and comprises a pair of outwardly swinging hinged members, material on the trackway impinging on the doors opening the same to discharge said material.

5. A drying oven comprising a U-shaped housing structure, a portal at the foot of each leg of the U, means providing a trackway on the floor of the oven from one portal through. the housing to the other portal, a door for each portal, heating means in the corner formed by each leg and the closed end of the U, an air outlet at each portal connected to the intake side of its respective heating means, a pair of spaced air inlets in the closed end of the U connected to the output side of the respective heating means, whereby heated air enters the housing centrally thereof and exits at each end thereof at the portals, a conveyor near the top of the oven to pass material over the material being traveled along the trackway, said conveyor extending outwardly from the housing at one end to deposit the material thereon adjacent a portal for reentrance of the material into the oven on a lower level.

6. The process of treating fiber comprising the steps of passing the fiber in a generally continuous strand along a predetermined path through an enclosure, recirculating hot air in the enclosure, heating the air exteriorly of the enclosure and completely separated from any flame, cutting the fiber strand into butts, and repassing the butts through the enclosure along a separate path, the strand and butts being passed through the enclosure simultaneously.

7. The process of treating fiber comprising the steps of passing the fiber in a generally continuous strand along a path through an enclosure, recirculating hot air in the enclosure, heating the air exteriorly of the enclosure and completely separated from any flame, cutting the fiber strand into butts, and repassing the butts along a different path through the enclosure while preventing escape of hot air at the entrance point of the fiber butts into the enclosure.

References Cited in the file of this patent UNITED STATES PATENTS 1,700,994 Buck Feb. 5, 1929 1,720,113 Argabrite July 9, 1929 2,128,697 Ettl Aug. 30, 1938 2,385,962 Barnett Oct. 2, 1945 2,386,286 Beckley Oct. 9, 1945 

6. THE PROCESS OF TREATING FIBER COMPRISING THE STEPS OF PASSING THE FIBER IN A GENERALLY CONTINUOUS STRAND ALONG A PREDETERMINED PATH THROUGH AN ENCLOSURE RECIRCULATING HOT AIR IN THE ENCLOSURE, HEATING THE AIR EXTERIORLY OF THE ENCLOSURE AND COMPLETELY SEPARATED FROM ANY FLAME, CUTTING THE FIBER STRAND INTO BUTTS, AND REPASSING THE BUTTS THROUGH THE ENCLOSURE ALONG A SEPARTE PATH, THE STRAND AND BUTTS BEING PASSED THROUGH THE ENCLOSURE SIMULTANEOUSLY. 